If you only smoke when you're buzzed, you might want to reconsider: Those occasional late-night puffs could intensify your hangover in the morning, according to a new study in the Journal of Studies on Alcohol and Drugs.

Researchers asked 113 people to complete an online survey that broke down their smoking habits, drinking habits, and hangover symptoms over an 8-week period. The results: People who drank heavily--roughly five or six beers in an hour--and smoked on the same day were more likely to have a hangover than those who just stuck to booze. (Enjoy a beer without the belly: Check out the 9 Best Low-Calorie Beers.)

What gives? Researchers aren't sure, but have a couple theories. For starters, previous data suggests that nicotine receptors in your brain can affect the way you respond to alcohol, Damaris Rohsenow, Ph.D., lead study author and a professor of behavioral science at the Center for Alcohol and Addiction Studies at Brown University, tells MensHealth.com. And when you smoke, that nicotine may trigger the release of dopamine--your brain's feel-good chemical.

In other words, the nicotine receptors in your brain may influence how much you drink, Rohsenow explains. Another hypothesis: The nicotine may lead to a release of cytokines, a protein that's secreted when your brain encounters injury. That can result in inflammation in your brain, which ultimately leads to nausea and headaches, she says.

So the next time your buddy offers you a light outside of the bar, you're better off passing on the cigs--that is, unless you enjoy having a splitting headache. Didn't take our advice? Then at least avoid the 3 Hangover Mistakes You Always Make.